%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-4-21 on page II-172 in "mathtools, interval --- Properly spaced intervals".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{165.0pt}

%StartShownPreambleCommands

%StopShownPreambleCommands

\begin{document}
$ [a,d\mathclose{[} = [a,b] + \mathopen{]}b,c] +
   \mathopen{]}c,d\mathclose{[} - [d,e\mathclose{[} $
\end{document}
